1. Field of the Invention
The present invention relates to an image processing apparatus and method of combining an original image and another image.
2. Background of the Invention
An image combining function is a useful function in information processing apparatuses such as a personal computer and in image processing apparatuses such as a scanner, printer, facsimile machine, copying machine, and digital composite machine having functions of these apparatuses. In a personal computer, for example, a CPU which executes predetermined image processing software functions as an image combining unit for executing image combination. Likewise, in a digital composite machine, an image processor included in a controller functions as an image combining unit.
Conventionally, these apparatuses combine a plurality of images by processing raster files of the whole images. For example, as shown in FIG. 23, raster files (images A and B) of whole images to be combined are input as objects to be processed to an image combining unit, and combined to obtain a combined image C.
Unfortunately, if entire images are used as objects to be combined as in the conventional apparatuses, portions which need not be combined are also processed as objects to be combined, so the combining process wastes time. In addition, since whole images are processed, the hardware resources necessary for the combination become enormous depending on the sizes of the images. Also, the control and management loads on a CPU during image combination increase.